Ideas? help? First motorhome , fuel issue, 81 P30 454

I had an Allegro, 1985, 23' with a 454. It suffered from massive vapor lock issues. Since I bought it new I called old man Tiffin and he finally relented and sent me an extra fuel pump to install in front of the fuel tank which solved the problem. The 454 was a real Turkey. Went thru 2 sets of manifolds until I changed to stainless Steel. It also burned up spark plug wires. Tiffin attributed all of these problems to the engine not getting sufficient airflow/intake.